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"For the moment, we have no explanation", the mystery of the conger eels washed up on the beaches of southern Finistère
Written by Carole Collinet-Appéré
Published on 08/26/2024 at 12:57 p.m.
Updated on 08/26/2024 at 3:51 p.m.
A large number of conger eels have washed up on the Finistère coast, between Concarneau and Le Guilvinec. Sudden illness? High tides? Toxin released by microalgae that appeared a week ago? The causes of mortality raise doubts and questions.
The first corpses of conger eels, also called sea eels, were observed on Thursday, August 22, 2024, in the port of Concarneau. The next day, around ten of them were found dead on the beach of Sables-Blancs. Some 200 individuals thus washed up between Concarneau and Guilvinec, in southern Finistère.
The phenomenon is rare enough to raise questions. "I have been working at the Concarneau marine station for 27 years, this is the first time I have seen a mass stranding" notes Samuel Iglesias, lecturer at the natural history museum.
"The possibility of a dumping by fishermen has been ruled out because there are too many bodies and the phenomenon is too widespread on the coast."
Samuel Iglesias
Researcher at the Concarneau marine station
The researcher is doubtful. No explanation for the causes of death has been given to date. However, several avenues have been explored. Starting with the rejection by fishermen of this fish which does not have a great market value. However, this is quickly dismissed, "because there are too many corpses and the phenomenon is too widespread on the coast" specifies Samuel Iglesias.
He even briefly considers that this mortality is linked to the reproduction of conger eels: when the eggs are released, the animal dies. "The reproduction cycle does not take place every year and is similar to that of eels, " he relates. " They reproduce offshore and undergo a sort of metamorphosis that decalcifies them. There, there is no decalcification and plankton monitoring shows that there are no conger eel larvae. So I also rule out this hypothesis . "
Toxin? Disease?
Another hypothesis: a bloom of marine microalgae was reported in the bay of Concarneau a week ago, making the water very brown. Did they release a toxin that could have killed the conger eels? "There is nothing to suggest that there is a cause and effect link," says the researcher at the marine station. " Why would this toxin only attack conger eels and not other fish? "
Except that since the first observations, Samuel Iglesias has received other reports of strandings which concern, this time, sea bass in the Saint-Laurent cove in La-Forêt-Fouesnant, gilthead sea bream as well as around forty lobsters in the Glénan. Enough to thicken the mystery a little more.
The scientist does not, however, rule out the possibility of a sudden illness in the conger eels, which are nevertheless robust and capable of living in 2 metres of water. "In Concarneau, they are found under large rocky blocks, they have the same habitat as lobsters," he says. " If they were weakened, these fish could have been trapped at low tide, given the high tidal coefficients, and died from lack of oxygen. Those that we found were most certainly living close to the edge," the specialist adds cautiously.
Analyses in progress and closed beaches
The mystery remains and is likely to remain so. The lecturer at the natural history museum is not able to conduct toxicological analyses or perform an autopsy on the bodies. "That's not my job, " he says. "I observe the phenomenon and archive it ." He knows, however, that the massive nature of the stranding implies "a very specific cause of mortality." Yes, but which one?
On the Ifremer side, in Concarneau, microalgae samples have already been taken, as soon as the bloom phenomenon appeared and before the death of the conger eels. "Bio-molecular analyses are underway" confirm Kenneth Mertens and Aourgan Terre. The taxonomy researcher and the laboratory technician indicate that they will make it possible to "identify the species of algae and to know if it produces toxins". The results will be known in a few weeks.
The Concarneau town hall has decided to close access to the beaches "until further notice" , due to the many stranded conger eels. "Water sports, swimming, walking and all other leisure activities are strictly prohibited" it specifies in a decree taken on August 25, mentioning the possibility of a "health risk".
"No question of swimming"
Anne, who is a regular at the Sables-Blancs beach, is categorical: for her, fishing is the cause. "The poor congers did not die from pollution," she says. " I am sure that they were dumped off the coast of the Glénan by big trawlers, they throw them away because they do not sell them at auction, these fish."
The collection of sea eel corpses on this beach in Concarneau is underway. "It doesn't smell good," says André, a longe-côte enthusiast who preferred to postpone his session to another day. " There are also some in the water, so swimming is out of the question, especially since we don't know the origin of their problem or why they are dying en masse like that," sighs the man, adding that he has "never seen anything like it."
https://france3-regions.francetvinf...-sur-les-plages-du-sud-finistere-3022406.html
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"It's the first time I've seen a mass stranding", hundreds of conger eel carcasses wash up on Breton beaches
Hundreds of conger eel carcasses have been found on the beaches of Finistère in recent days
Animals , Environment , Hunting - Fishing
Published on08/26/2024 at 4:00 p.m. , updated at 16:03
The editorial staff
The essential Conger eels, a fish also called sea eels, have been washing up first in their dozens and then in their hundreds on the beaches of southern Finistère in recent days. A phenomenon that has yet to be explained and has left scientists perplexed.
The first bodies were observed on Thursday, August 22 in the port of Concarneau (Finistère). The next day, dozens were found dead on the beach of Sables-Blancs. In total, some 200 conger eels, also called sea eels, have washed up in recent days in the south of Finistère between Concarneau and Guilvinec, reports France 3 .
A still unexplained phenomenon that led to the closure of Concarneau beach from August 25 to 27. "Water sports, swimming, walking and all other leisure activities are prohibited there," states the decree from the town hall.
How to explain the sudden mortality of fish?
Disease, toxin, tides… The cause of the mortality remains unknown and is puzzling specialists. "I have worked at the Concarneau marine station for 27 years, this is the first time I have seen a mass stranding," Samuel Iglesias, lecturer at the natural history museum, told France 3. However, he rules out the possibility of a dumping by fishermen "because there are too many bodies and the phenomenon is too widespread on the coast."
The other hypothesis explored is that of a toxin released by algae that appeared a week ago in the bay of Concarneau and which turned the water brown. "There is nothing to suggest that there is a cause and effect link. Why would this toxin only attack conger eels and not other fish?" asks the researcher. Except that since then, he has received other reports that gilthead sea bream and lobsters had washed up on other beaches. The scientist also suggests that it was a disease. The mystery therefore remains. Analyses are also underway.
https://www.ladepeche.fr/2024/08/26...chouent-sur-les-plages-bretonnes-12159984.php
"For the moment, we have no explanation", the mystery of the conger eels washed up on the beaches of southern Finistère
Written by Carole Collinet-Appéré
Published on 08/26/2024 at 12:57 p.m.
Updated on 08/26/2024 at 3:51 p.m.
A large number of conger eels have washed up on the Finistère coast, between Concarneau and Le Guilvinec. Sudden illness? High tides? Toxin released by microalgae that appeared a week ago? The causes of mortality raise doubts and questions.
The first corpses of conger eels, also called sea eels, were observed on Thursday, August 22, 2024, in the port of Concarneau. The next day, around ten of them were found dead on the beach of Sables-Blancs. Some 200 individuals thus washed up between Concarneau and Guilvinec, in southern Finistère.
The phenomenon is rare enough to raise questions. "I have been working at the Concarneau marine station for 27 years, this is the first time I have seen a mass stranding" notes Samuel Iglesias, lecturer at the natural history museum.
"The possibility of a dumping by fishermen has been ruled out because there are too many bodies and the phenomenon is too widespread on the coast."
Samuel Iglesias
Researcher at the Concarneau marine station
The researcher is doubtful. No explanation for the causes of death has been given to date. However, several avenues have been explored. Starting with the rejection by fishermen of this fish which does not have a great market value. However, this is quickly dismissed, "because there are too many corpses and the phenomenon is too widespread on the coast" specifies Samuel Iglesias.
He even briefly considers that this mortality is linked to the reproduction of conger eels: when the eggs are released, the animal dies. "The reproduction cycle does not take place every year and is similar to that of eels, " he relates. " They reproduce offshore and undergo a sort of metamorphosis that decalcifies them. There, there is no decalcification and plankton monitoring shows that there are no conger eel larvae. So I also rule out this hypothesis . "
Toxin? Disease?
Another hypothesis: a bloom of marine microalgae was reported in the bay of Concarneau a week ago, making the water very brown. Did they release a toxin that could have killed the conger eels? "There is nothing to suggest that there is a cause and effect link," says the researcher at the marine station. " Why would this toxin only attack conger eels and not other fish? "
Except that since the first observations, Samuel Iglesias has received other reports of strandings which concern, this time, sea bass in the Saint-Laurent cove in La-Forêt-Fouesnant, gilthead sea bream as well as around forty lobsters in the Glénan. Enough to thicken the mystery a little more.
The scientist does not, however, rule out the possibility of a sudden illness in the conger eels, which are nevertheless robust and capable of living in 2 metres of water. "In Concarneau, they are found under large rocky blocks, they have the same habitat as lobsters," he says. " If they were weakened, these fish could have been trapped at low tide, given the high tidal coefficients, and died from lack of oxygen. Those that we found were most certainly living close to the edge," the specialist adds cautiously.
Analyses in progress and closed beaches
The mystery remains and is likely to remain so. The lecturer at the natural history museum is not able to conduct toxicological analyses or perform an autopsy on the bodies. "That's not my job, " he says. "I observe the phenomenon and archive it ." He knows, however, that the massive nature of the stranding implies "a very specific cause of mortality." Yes, but which one?
On the Ifremer side, in Concarneau, microalgae samples have already been taken, as soon as the bloom phenomenon appeared and before the death of the conger eels. "Bio-molecular analyses are underway" confirm Kenneth Mertens and Aourgan Terre. The taxonomy researcher and the laboratory technician indicate that they will make it possible to "identify the species of algae and to know if it produces toxins". The results will be known in a few weeks.
The Concarneau town hall has decided to close access to the beaches "until further notice" , due to the many stranded conger eels. "Water sports, swimming, walking and all other leisure activities are strictly prohibited" it specifies in a decree taken on August 25, mentioning the possibility of a "health risk".
"No question of swimming"
Anne, who is a regular at the Sables-Blancs beach, is categorical: for her, fishing is the cause. "The poor congers did not die from pollution," she says. " I am sure that they were dumped off the coast of the Glénan by big trawlers, they throw them away because they do not sell them at auction, these fish."
The collection of sea eel corpses on this beach in Concarneau is underway. "It doesn't smell good," says André, a longe-côte enthusiast who preferred to postpone his session to another day. " There are also some in the water, so swimming is out of the question, especially since we don't know the origin of their problem or why they are dying en masse like that," sighs the man, adding that he has "never seen anything like it."
https://france3-regions.francetvinf...-sur-les-plages-du-sud-finistere-3022406.html
---------------------------
"It's the first time I've seen a mass stranding", hundreds of conger eel carcasses wash up on Breton beaches
Hundreds of conger eel carcasses have been found on the beaches of Finistère in recent days
Animals , Environment , Hunting - Fishing
Published on08/26/2024 at 4:00 p.m. , updated at 16:03
The editorial staff
The essential Conger eels, a fish also called sea eels, have been washing up first in their dozens and then in their hundreds on the beaches of southern Finistère in recent days. A phenomenon that has yet to be explained and has left scientists perplexed.
The first bodies were observed on Thursday, August 22 in the port of Concarneau (Finistère). The next day, dozens were found dead on the beach of Sables-Blancs. In total, some 200 conger eels, also called sea eels, have washed up in recent days in the south of Finistère between Concarneau and Guilvinec, reports France 3 .
A still unexplained phenomenon that led to the closure of Concarneau beach from August 25 to 27. "Water sports, swimming, walking and all other leisure activities are prohibited there," states the decree from the town hall.
How to explain the sudden mortality of fish?
Disease, toxin, tides… The cause of the mortality remains unknown and is puzzling specialists. "I have worked at the Concarneau marine station for 27 years, this is the first time I have seen a mass stranding," Samuel Iglesias, lecturer at the natural history museum, told France 3. However, he rules out the possibility of a dumping by fishermen "because there are too many bodies and the phenomenon is too widespread on the coast."
The other hypothesis explored is that of a toxin released by algae that appeared a week ago in the bay of Concarneau and which turned the water brown. "There is nothing to suggest that there is a cause and effect link. Why would this toxin only attack conger eels and not other fish?" asks the researcher. Except that since then, he has received other reports that gilthead sea bream and lobsters had washed up on other beaches. The scientist also suggests that it was a disease. The mystery therefore remains. Analyses are also underway.
https://www.ladepeche.fr/2024/08/26...chouent-sur-les-plages-bretonnes-12159984.php